For various purposes such as military, construction and environmental protection, the necessity of a ground image obtained through aerial photographing is gradually increased. A flight vehicle having a camera is used in the aerial photographing. In the related art, when the ground image is obtained, a fixed wing flight vehicle having a camera performs a photographing operation, while flying along a preset flight route.
However, when the aerial photographing is performed using the fixed wing flight vehicle, first, a photographing area and the flight route which can cover the entire photographing area are set, and then, while the fixed wing flight vehicle flies along the preset flight route, the camera is operated so as to obtain the ground image. In general, since the fixed wing flight vehicle flies at a high speed, and cannot stay in the air, the obtained image is verified after a flight of the fixed wing flight vehicle is finished. When there is something wrong with the obtained ground image, or a target object is not photographed properly, the fixed wing flight vehicle should fly again over the entire photographing area so as to obtain a proper image.
Furthermore, even when the fixed wing flight vehicle flies again to rephotograph a place corresponding to the defected ground image, it is very difficult to obtain an image of the same position as a previously photographed position, or to perform a photographing operation under the same conditions as previous photographing conditions, because the fixed wing flight vehicle cannot stay at a certain position. Therefore, to construct terrain data with respect to one photographing area, it might be necessary to repeatedly perform the flight of the flight vehicle several times, and thus it can be costly and time-consuming.